1. Field of the Invention
The invention relates to an apparatus and a method for the automatic regulation and control of an irrigation of plants in accordance with the preamble of the independent patent claims. It relates, in particular, to an apparatus and a method for an optimized irrigation time without water excess and without the soil drying out.
2. Description of Related Art
When plants are irrigated, in particular lawns or agricultural land, use is made of irrigation systems that are controlled by a timer. The user can set, on the latter, both the instant and the duration of the irrigation, there being on the market various timers for the control of a variety of irrigation zones and with different levels of complexity.
This type of irrigation control is low in flexibility, that is to say irrigation is performed over the preset time duration and at the preset instants, irrespective of the effective need of the plants that are to be irrigated.
So-called rain sensors are also known that, when rain is falling, measure the amount of rain and block the timer when a defined amount is exceeded so that no irrigation is performed while it is raining.
It is true that this method avoids an irrigation during or after a rain event. For example, in cool or rainless weather irrigation is performed, however, though sufficient moisture is present in the soil and there is thus no need to irrigate.
In recent years, soil moisture sensors have been connected to timers. These sensors measure the current moisture in the soil and enable the timer, and thus initiate watering, only upon falling below a critical soil moisture that can be set. Most of these soil moisture sensors are expensive to procure and maintenance-intensive, and the measurement result depends strongly on other parameters, such as the fertilizer content. They have therefore not been able to establish themselves on the market. However, a novel soil moisture sensor that does not have these disadvantages has also been developed in accordance with WO 2006/081693.
Such an improved soil moisture sensor can now be used to prevent irrigation from being performed unnecessarily. However, the amount of water administered per watering cycle is still set by the user on the timer, and is therefore fixedly prescribed. The amount of water effectively required can, however, deviate strongly from the set amount, and it also varies with short term and long term climatic fluctuations. Experience shows that in the case of crops, in particular, once a watering time has been set, users tend to adapt to the current climatic conditions only in exceptional cases and mostly not change it throughout the entire year.
When consideration is given to the ever more topical problems associated with rising water consumption, particularly in countries with scarce water reserves, the aspect of carefully managing water as a resource becomes very important. The avoidance of unnecessary water consumption belongs here, as well. Immense quantities of water (80% of the entire water consumption) are used globally in the irrigation of crops and green areas. It is estimated that half thereof could be saved by intelligent irrigation.
It is therefore an object of the invention to provide an intelligent method for the control and regulation of an irrigation time with the aid of which, with an automatically set watering time, no excess water is poured and, on the other hand, the soil is prevented from drying out.